The invention concerns a device for charging and discharging from a tilting smelting furnace, a removable crucible.
More particularly, the device of the invention is designed to place in a furnace a cylindrical crucible containing a compact cylindrical smelting charge, and to extract the crucible. It is suitable in particular when the furnace is part of an installation in which smelting and tapping takes place in a vacuum. The invention also concerns an installation in which smelting and tapping take place in a vacuum equipped with this device.
Already known are installations in which smelting and tapping take place in a vacuum equipped with a device for charging and discharging permitting working through a lock-chamber. The device of the invention belongs to a type comprising:
a charging shovel in the form of a gutter, the cross section of which is in the shape of a segment of a circle, designed, on the one hand, to introduce the crucible and the charge through the lock-chamber into the tilting furnace in the horizontal position, and, on the other hand, to extract the crucible after tapping;
a rectilinear rod, with the shovel attached to its end, the rod and the shovel being approximately coaxial;
means for maintaining the rod horizontally in alignment with the tilting furnace in the horizontal position;
finally, means for moving the rod in travel in the direction of its axis.
In a known device of the type defined above, the radius of the cross section of the shovel is at least equal to the outside semi-diameter of the crucible such that the shovel can accept the crucible, charged or not. The rod is bored and carries in its borehole a rectilinear lever perceptibly longer than the rod, and the device has means for causing this lever to penetrate the shovel by sliding and to momentarily maintain it in a fixed position in space in order to push the charge and the crucible toward the bottom of the furnace during extraction of the shovel, despite the friction this exerts on the crucible.
This device of known type is quite appropriate for its purpose, but at the same time has the following inconvenience, one that is particularly troublesome when the crucible is fragile, and expensive. The crucible is subjected to intense friction during release of the shovel after charging, and during engagement of the shovel prior to extraction of the crucible, and, in addition, the crucible falls a short distance to the floor of the furnace when the shovel is released.